Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
/**
 * Created by Martin on 6/17/2017.
 */
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
import java.io.PrintWriter;

public class Main {

    public static void main(String[]args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw = new PrintWriter(System.out);
        StringTokenizer st = new StringTokenizer(br.readLine());
        int N = Integer.parseInt(st.nextToken());
        int M = Integer.parseInt(st.nextToken());
        int[][] g = new int[N][M];
        for (int i = 0; i < N; i++) {
            st = new StringTokenizer(br.readLine());
            for (int j = 0; j < M; j++) {
                g[i][j] = Integer.parseInt(st.nextToken());
            }
        }

        List<M> moves = new ArrayList<>();
        while (true) {
            boolean found = false;
            int mv = Integer.MAX_VALUE;
            int mi = 0, mj = 0;
            for (int i = 0; i < N; i++) {
                for (int j = 0; j < M; j++) {
                    if (g[i][j] < mv && g[i][j] > 0) {
                        mv = g[i][j];
                        mi = i;
                        mj = j;
                        found = true;
                    }
                }
            }
            if (!found) {
                pw.println(moves.size());
                for (M move : moves) {
                    pw.println((move.type == 0 ? "row" : "col") + " " + move.num);
                }
                break;
            }
            boolean rowOk = true;
            for (int i = 0; i < M; i++) {
                if (g[mi][i] == 0) {
                    rowOk = false;
                    break;
                }
            }
            boolean colOk = true;
            for (int i = 0; i < N; i++) {
                if (g[i][mj] == 0) {
                    colOk = false;
                    break;
                }
            }
            if (rowOk && colOk) {
                if (M > N) colOk = false;
                else rowOk = false;
            }

            if (rowOk) {
                for (int i = 0; i < M; i++) g[mi][i]--;
                moves.add(new M(0, mi + 1));
            }
            else if (colOk) {
                for (int i = 0; i < N; i++) g[i][mj]--;
                moves.add(new M(1, mj + 1));
            }
            else {
                pw.println(-1);
                break;
            }
        }
        pw.flush();
    }

    private static final class M {
        int type, num;

        public M(int type, int num) {
            this.type = type;
            this.num = num;
        }
    }

    public static void debug(Object...args) {
        System.out.println(Arrays.deepToString(args));
    }
}